1. Field of the Invention
The invention relates to an electrical cable holding case that can prevent oil from leaking through electrical cables laid out within an oil cover such as a transmission.
2. Related Art
FIG. 6 is an exploded perspective view of a conventional electrical cable holding case that prevents oil leakage disclosed in Japanese Unexamined Patent Publication No. 4-261318; and FIG. 7 is a longitudinal sectional view of the electrical cable holding case as assembled.
In these figures, reference numeral 1 denotes a case main body made of synthetic resin; and 2, an oil cover such as a transmission (reference numeral 3 denotes the interior of the oil cover in FIG. 7). A flange portion 6 for an open hole 5 of the cover 2, an O ring 7, and a setting groove 8 are annularly arranged over the outer circumference of a cylindrical wall 4 of the case main body 1. A pair of flexible retaining pawls 9 are also provided, projecting in the axial direction.
There is arranged inside cylindrical wall 4 a compartment wall 11, having a plurality of electrical cable lead holes 10 disposed annularly therein. Also, a plurality of partitioned chambers 13 communicating with the electrical cable lead holes 10 are formed by arranging partition walls 12 upright in the radial direction from the center of the compartment wall 11. Each partitioned chamber 13 has an opening 14 facing the interior of the cover 2, and each opening 14 is continuous to an empty chamber 15 surrounded by a cylindrical wall 4a. Further, frame pieces 17 having retaining windows 16 are projected on an end of the cylindrical wall 4a. An empty chamber 18 surrounded by a cylindrical wall 4b that faces the outside of the cover 2 is continuous from the compartment wall 11. Radially extending ribs 19 are arranged between the adjacent electrical cable lead holes 10 on the outer surface of the compartment wall 11. In FIGS. 6 and 7, reference numerals 20 and 21 denote resin charging holes.
In FIGS. 6 and 7, reference numeral 22 denotes a rear holder made of synthetic resin and fitted into the empty chamber 15 of the case main body 1. A plurality of electrical cable insertion holes 24 corresponding to the partitioned chambers 13 of the case main body 1 and resin charging holes 25 are arranged on a circular bottom wall 23 of the rear holder 22. Retaining pieces 28 are disposed on an end of a circumferential wall 26 of the rear holder 22, the wall 26 being formed continuously from the bottom wall 23. Retaining pieces 28 have retaining projections 27 for the corresponding retaining windows 16 of the case main body 1.
Further, reference numeral 29 denotes a watertight rubber plug that is fitted into the other empty chamber 18 of the case main body 1. A plurality of small-diameter electrical cable attaching holes 30 corresponding to the electrical cable head holes 10 in the compartment wall 11 are arranged in the rubber plug 29. Reference numeral 31 denotes a blank plug made of synthetic resin. Blank plugs are inserted into the electrical cable attaching holes into which no electrical cable 32 is to be inserted.
An electrical cable 32 exits from the interior 3 of the cover 2. The electrical cable 32 is formed by unsheathing an intermediate sheath 33 of a single sheathed electrical cable and fixing a joint terminal 35 to the exposed conductor portion 34 by caulking. The joint terminal 35 is made of a metal plate and serves as a retaining member.
One end of the electrical cable 32 is inserted into the insertion hole 24 of the rear holder 22, and the other is inserted into the attaching hole 30 of the rubber plug 29 via the lead hole 10 from the partitioned chamber 13 of the case main body 1. The joint terminal 35, serving as a retaining member, is accommodated in the partitioned chamber 13 and held between the bottom wall 23 of the rear holder 22 and the compartment wall 11; that is, the rear holder 22 is fitted into and retained in the empty chamber 15. The rubber plug 29 is fitted into the other empty chamber 18 and forms a gap 36 with respect to the compartment wall 11, the gap 36 being equal to the height of the rib 19.
Furthermore, as shown in FIG. 7, a hardening flexible resin material 37 such as silicon resin is injected into the partitioned chambers 13 and the gap 36 from the resin charging holes 25 of the rear holder 22, thereby embedding both the conductor portion 34 and one sheathed end portion 33a of the electrical cable 32. Also, the resin material 37 is filled in the rear holder 22, thereby sealably holding the other sheathed end portion 33b. The hardening flexible resin material 37 exhibits satisfactory sealability while flexibly fitted with the conductor portion 34 under thermal expansion or contraction.
Since each electrical cable 32 in the interior of the oil cover is bent so as to be L-shaped as shown in FIG. 8 because of space restrictions within an automobile and this condition is persistently maintained by a taping 38 provided to protect the electrical cables, this prevents the charged resin material 37 from being fitted with the bending of the electrical cables 32, which in turn encourages cracks c to develop at the interfaces between the electrical cables and the resin material and in the resin material itself. As a result, the cracks c damage the sealability of the case main body.